you are right, but you are misplacing the blame. it's not that you dont own your phone, it's that you dont own your bank account and the bank can dictate how you access it
The National Credit Union Federation of Korea (NACUFOK) represents over 800 member-owned unions (https://www.cu.co.kr/english/main.do), and then there is the even larger Saemaul Geumgo (MG) network which operates as community credit cooperatives with millions of members. These people ostensibly own their "bank" accounts.